Exhaust gas guide sections for exhaust gas turbochargers which comprise an actuator for regulating a fluid flowing though the exhaust gas guide section, generally exhaust gas, are known. The actuator is intended for opening and closing of a bypass duct in the through-flow exhaust gas guide section for bypassing a turbine wheel of the exhaust gas guide section, which is rotatably arranged in the exhaust gas guide section in a wheel chamber of the exhaust gas guide section. It comprises a wastegate for opening and closing of a flow cross section of the bypass duct. By means of such an actuator, it is possible to completely or partially bypass the turbine wheel in certain operating points of the exhaust gas turbocharger, in particular in operating points which exhibit large flow volumes so that an efficient operation of the exhaust gas turbocharger is made possible. The efficient operation of the exhaust gas turbocharger is dependent on a certain opening characteristic of the actuator, which is to be adapted to the requirements of a combustion engine which is connected with the exhaust gas turbocharger.
DE 198 24 913 A1 discloses an exhaust gas guide section for an exhaust gas turbocharger with an actuator, whose opening characteristic exhibits a progressive course. Depending on a travel of the wastegate of the actuator, an opening cross section of a bypass duct of the exhaust gas guide section progressively increases, in particular exponentially, with increasing travel starting from a closed position. Thus, a progressive opening characteristic is given which is suited for the described application.
WO 2010/039596 A2 also discloses an exhaust gas guide section for an exhaust gas turbocharger with an actuator, whose wastegate exhibits a progressive opening characteristic, starting from a closed position of the wastegate.